Need more marines! As it is, you have 1 tac squad. You'll need at least 1 more to make just a basic list of 1 HQ and 2 Troops. Put the flamer away, it's mostly worthless. Buy some more regular marines, 3 more assualt marines to fill out your assault squad. And like you say, maybe another dreadnaught. In 1500 points, I'd only field the chaplain, and attach him to your assault squad. Grab 3 more missile launchers, add 4 regular marines and you'd have a great dev squad.